Gordon Brown has denied threatening to "destroy" News International during a phone call to Rupert Murdoch after The Sun switched its allegiance to the Conservatives.
Lawyers acting on behalf of the former Labour prime minister read a letter to the Leveson Inquiry claiming that former Sun editor Kelvin MacKenzie's claims about such an incident were "untrue".
Giving evidence last week, MacKenzie confirmed what he had told a Leveson Inquiry seminar in October - that Murdoch had described Mr Brown "roaring" down the phone at him after The Sun overshadowed his 2009 Labour Party conference speech by deciding to endorse Tory leader David Cameron at the next election.
Brown was alleged to have told the News International boss: "You are trying to destroy me and my party. I will destroy you and your company."
But Brown rejected the claims as false.
"The story is completely untrue," his lawyers wrote. "It is important that it does not become accepted as fact."
Their letter said: "Mr Brown has a clear recollection of the calls he had with Mr Murdoch when he was Prime Minister.
"He had no such conversation with Mr Murdoch at any time during the conference. Thus the words attributed to him by Mr MacKenzie were not said by him to Mr Murdoch, and the statement attributed to Mr Murdoch by Mr MacKenzie is likewise factually wrong.
"The account is not an accurate reflection of events."
MacKenzie's "hearsay statement" was not tested as to its reliability or credibility in the inquiry, the lawyers added.
The Sun's switch to the Conservatives was announced on September 30 2009, under the headline "Labour's lost it".
It came 12 years after former prime minister Tony Blair successfully wooed the newspaper into supporting Labour.